1 W Ku-band AlGaAs/GaAs power HBTs with 72% peak power-added efficiency

High power and high-efficiency multi-finger HBTs (heterojunction bipolar transistors) have been successfully realized at Ku-band by using emitter ballasting resistors and a PHS (plated heat sink) structure. An output power of 1 W with power added efficiency (PAE) of 72% at 12 GHz has been achieved from a ten-finger HBT with the total emitter size of 300 /spl mu/m/sup 2/. 72% PAE with the output power density of 5.0 W/mm is the best performance in the HBTs of which the output powers are more than 1 W at Ku-band. >